The heart is the center of a person's circulatory system. It includes an electro-mechanical system performing two major pumping functions. The left portions of the heart draw oxygenated blood from the lungs and pump it to the organs of the body to provide the organs with their metabolic needs for oxygen. The right portions of the heart draw deoxygenated blood from the organs and pump it into the lungs where the blood gets oxygenated. In a normal heart, the sinoatrial node, the heart's natural pacemaker, generates electrical impulses, known as action potentials, that propagate through an electrical conduction system to various regions of the heart to excite myocardial tissues in these regions. Coordinated delays in the propagations of the electrical impulses in a normal electrical conduction system cause the various regions of the heart to contract in synchrony such that the pumping functions are performed efficiently.
A blocked or otherwise damaged electrical conduction system causes irregular contractions of the myocardium, a condition generally known as arrhythmia. Arrhythmia reduces the heart's pumping efficiency and hence, diminishes the blood flow to the body. A weakened myocardium has decreased contractility, also resulting in diminished blood flow. A heart failure patient usually suffers from both a damaged electrical conduction system and a weakened myocardium. The diminished blood flow results in insufficient blood supply to various body organs, preventing these organs to function properly and causing various symptoms. For example, in a patient suffering decompensated heart failure, an insufficient blood supply to the kidneys results in abnormal fluid retention and increased central vascular pressure, and hence, cardiogenic pulmonary edema as well as edema in other organs.
Cardiogenic pulmonary edema shares common symptoms with pulmonary diseases such as obstructive pulmonary diseases including asthma and chronic obstructive pulmonary disease (COPD). Such common symptoms include difficulty of breathing, wheezing, and shortness of breathing. Safe and effective treatment for heart failure patients with cardiopulmonary comorbidities depends on differentiation of cardiogenic pulmonary edema from pulmonary diseases such as asthma and COPD. For example, beta-blockers (or beta-adrenergic blockers, pharmaceutical agents) are used to treat heart failure by reducing myocardial oxygen demand, resulting in improved cardiac functional status. However, beta-blockers are also known for their side effects including potential worsening of pulmonary conditions. Thus, heart failure patients who also suffer from asthma or COPD should be monitored while taking beta-blockers. While patient examinations in a doctor's office provide for the diagnosis of whether a heart failure patient also suffers asthma, biweekly titration of beta-blockers presents a challenge to an efficient and effective treatment.
For these and other reasons, there is a need for an efficient method and system to monitor the treatment of heart failure patients with cardiopulmonary comorbidities.